Excellent questions! 
The 120mm rads would be installed such that the tubes are at the bottom.
In case of clearance issues, the order of rad and fan can be changed, and/or a slim fan can be used on the side bracket.
By the way, clearance can become an issue, only if the first PCI slot is populated.
In case of the Gigabyte board, this is a non issue, since the board does not use it.
In case of the ASUS board, the issue would present itself only for 4x dual-slot GPU installation.
When the rads are installed as I tried to describe, there is about 35mm clearance from the motherboard surface, meaning DIMM height of 32mm would be supported. I'm working on a change that would increase this.
There is about 275mm clearance for the top rad, along with 52mm rad+fan assembly on the front.
The changes I mentioned should increase this a bit too.
If it pans out, I hope to be impress with those changes
The 120mm rads would be installed such that the tubes are at the bottom.
In case of clearance issues, the order of rad and fan can be changed, and/or a slim fan can be used on the side bracket.
By the way, clearance can become an issue, only if the first PCI slot is populated.
In case of the Gigabyte board, this is a non issue, since the board does not use it.
In case of the ASUS board, the issue would present itself only for 4x dual-slot GPU installation.
When the rads are installed as I tried to describe, there is about 35mm clearance from the motherboard surface, meaning DIMM height of 32mm would be supported. I'm working on a change that would increase this.
There is about 275mm clearance for the top rad, along with 52mm rad+fan assembly on the front.
The changes I mentioned should increase this a bit too.
If it pans out, I hope to be impress with those changes
